Corresponding manipulators for diaphragms or multiple diaphragms are, for example, known from the transmission electron microscopes LEO 912 or LEO 922 manufactured and sold by LEO Elektronenmikroskopie GmbH of Oberkochen, Germany. From Japanese patent application 86-048248, it is known to produce a diaphragm for an electron microscope having multiple layers of an inner hard metal and an external layer of metal surrounding the hard metal. The metal surrounding the hard metal has a high thermal conductivity.
Notwithstanding the use of thermally high conducting transfer elements, thermal drifts nonetheless occur because of the remaining heating and the thermal expansion of the components of the manipulator associated therewith, especially when the energy flow incident on the diaphragms varies. This leads to the situation that the position of the switched-in diaphragms must be readjusted after a change of the energy flow.